PhysicsAn archer's bow applies a force to an arrow over a distance of 19cm, while firing it vertically upwards. If the arrow achieves a speed of 8.0m/s and the efficiency of the bow is 75%, determine the average force applied to the arrow by the bow. So far I have the Wnet for ...
January 28, 2015

PhysicsYes, if you go back to the post I don't understand the sqart or that whole equation at all, grade 11 physics! Sorry for replying late btw
January 27, 2015

PhysicsA soccer ball is kicked with a velocity of 12m/s, HORIZONTALLY off a building which is 8.5m high. What is the velocity of the ball after 1.25s? This is what I found so far: Vi = 12m/s Dx = 15.8049336m Dy = 8.5m Time it took for ball to hit floor 1.31707778s I used D=Vi(T) + 1/...
January 27, 2015

PhysicsI am sorry I do not know what sqart is, and also sorry for not replying sooner bobpursley, but I tried to solve it myself and this is what I did, perhaps I used sqart? Because V = D/T I decided to find Dx and Dy Found Dy using: D= Vi(1.25) + 1/2(9.8)1.25^2 Which gave me 7....
January 27, 2015

PhysicsA soccer ball is kicked with a velocity of 12m/s, HORIZONTALLY off a building which is 8.5m high. What is the velocity of the ball after 1.25s? This is what I found so far: Vi = 12m/s Dx = 15.8049336m Dy = 8.5m Time it took for ball to hit floor 1.31707778s I used D=Vi(T) + 1/...
January 27, 2015

Materials ScienceI can't understand the epsilon r, could you write it again? because it seems - nu ?(epsilon h - Epsilon L/E) and this is not unitless
October 1, 2014

statisticsIf 1,000 students take a test that has a mean of 40 minutes, a standard deviation of 8 minutes, and is normally distributed, how many would you expect would finish in between 24 and 48 minutes?
August 6, 2014

drivers' ed.Are there some merge points where some drivers are entering while other drivers are exiting in close proximity? I was trying to get on earlier today, and if I had accelerated too sharply, I would have come close to a vehicle that was straight ahead of me.
July 15, 2014

MathYour cell phone cost $40 per month plus $0.15 for each text message you send or receive. You have at most$45 to spend on your cell phone bill. What is the maximum number of text messages that you can send or receive next month?
May 4, 2014

scienceComplete the following sentence with the best phrase below. Removing just one species from an ecosystem B.would have little effect; unless it was a key stone D.would have a negative effect; especially if it was a keystone species
December 11, 2013

scienceWhich of the following pairs of terms could describe a bullfrog that is active at night and enters a state of complete inactivity during cold months? cooperation and hibernation aggression and circadian rhythm circadian rhythm and hibernation courtship and cooperation
December 11, 2013

mathThe vertex of a rectangle whose side lengths are 6 and 8 lies at the point (-4,6) in the rectangular coordinate plane. Which of the following points could be a vertex of this rectangle? (A) (2,-2) (B) (2,8) (C) (-4,-10) (D) (-4,-4) (E) (-10,2)
August 13, 2013

mathAt a certain grocery store, "a" customers each spend an average of $30 every "b" hours. How much revenue , in dollars, does the store collect in "c" hours?
August 13, 2013

Mathon Mindy's guitar, the frequency of a vibrating string varies inversely as the length of the string. When a guitar string of "s" inches in length that vibrates at a frequency of 80 cycles per second is shortened to 6 inches in length, it vibrates at a frequency ...
August 5, 2013

chemA beaker with 120mL of an acetic acid buffer with a pH of 5.00 is sitting on a benchtop. The total molarity of acid and conjugate base in this buffer is 0.100 M. A student adds 5.70mL of a 0.450M HCl solution to the beaker. How much will the pH change? The pKa of acetic acid ...
July 22, 2013

chemistryTo half of it (500. mL), you add 0.0100mol of hydrogen ions without changing the volume. What is the pH of the final solution?
July 22, 2013

ChemistryI have a Chemistry question which should be very simple but I do not know what significant figures are. Assuming the following numbers are measurements and using the rules for significant figures, determine the answer for the following calculation. (15.5/42)*219.5= 1. 81.0059 ...
January 10, 2013

Algebra2Write the standard form of the equation of the circle with the given center and radius. 1. center (-2, 0) and r = 3
November 29, 2012

Algebra2Write an equation for the line in point/slope form and slope/intercept form that has the given condition. 1. Passes through (3, 2) and is parallel to 2x-y=4 2. Passes through (-1, -1) and is perpendicular to y = 5/2x + 3
November 29, 2012

ScienceChemistry Enthalpy Calculations? Given the equation: CaO + H2O ----> Ca(OH)2 A 1 g sample of CaO is dissolved in 100 ml water with density 1.00g/ml. The temperature rise is 3.7 degrees C. The specific heat is 4.00 J/g*deg. 1. Calculate the heat (in J) absorbed/given off by ...
October 18, 2012

Mathfind all the numbers less then 100 that are the product of exactly three different prime numbers.
September 1, 2012

chemistryThe volume of a gas at 20 C and 0.4 atm is 10 mL. What volume will the same gas sample occupy at standard conditions?
February 8, 2011

PhysicsTwo electrostatic point charges of +60.0 uC and +50.c uC exert a repulsive force on each other of 175 N. What is the distance between the two charges? So let's say I use Coulomb's law would the repulsion of 175 N be considered the equivalent of the electric force? Can ...
January 17, 2011

PhysicsTwo electrostatic point charges of +60.0 uC and +50.c uC exert a repulsive force on each other of 175 N. What is the distance between the two charges?
January 16, 2011

Physics (Final Review)Ok so tomorrow is my Physics final and I have so much depending on this one test ( all my other grades are 80 and above but this one is a low 70). I have studied for the final but if anyone could supply me with a list of most know formulas for physics I would really appreciate...
December 13, 2010

Physics ( check answers)Question 1 A 0.50 kg football is thrown with a velocity of 15 m/s to the right. A stationary receiver catches the ball and brings it to rest in 0.020s . What is the force exerted on the receiver? So I used mvf-mvi/change(t) I got 375 for that one... Question 2 A 0.40 kg soccer...
December 9, 2010

Physics ( check answers)Question 1 A 0.50 kg football is thrown with a velocity of 15 m/s to the right. A stationary receiver catches the ball and brings it to rest in 0.020s . What is the force exerted on the receiver? So I used mvf-mvi/change(t) I got 375 for that one... Question 2 A 0.40 kg soccer...
December 9, 2010

Pre-CalculusI want to learn how to find the domain, holes, x-intercepts, y- intercepts, vertical asymptotes, and horizontal asymptotes of a rational function. I know it is against the rules in jiskha to do the homework for the students but if I have been looking over my notes and I just ...
December 2, 2010

AP GovernmentI have a few question I need answered, if anyone could help I would really appreciate it... 2. All Presidents but one have been a. Protestant b. Catholic c. Evangelical Christian d. Atheist e. Hare Krishna 16. A mid term election is a. A Congressional election that is not ...
November 15, 2010

Physics(Checking answer)Sorry for the re-post but I really need to know this, but now I just want to know if the question is right. A spring with a force of 5.2 N/m has a relaxed length of 2.45. When a mass is attached to the end of the spring and allowed to come to rest. the vertical length of the ...
November 4, 2010

Physics ( elestic potential energy)A spring with a force of 5.2 N/m has a relaxed length of 2.45. When a mass is attached to the end of the spring and allowed to come to rest. the vertical length of the spring is 3.57m. Calculate the elastic potential energy stored in the spring.
November 4, 2010

Physics-Kinetic energyTwo 2.0 g bullets are fired with speeds of 40.0 m/s and 80.0 m/s, respectively. What are their kinetic energies? Which bullet has more kinetic energy? What is the ratio of their kinetic energies? A car has kinetic enery of 4.32* 10^5 when traveling at a speed of 23m/s. What is...
October 30, 2010

AP Government(Research question so not really)I am supposed to make an annotated bibliography for all the research I have done for my history fair project. Thing is I don't know how to make an annotated bibliography and I have looked up examples and I am not sure if you can do it with 50 sources. I am supposed to use ...
October 30, 2010

Physics- WorkA worker pushes a 1.50*10^3 N crate with a horizontal force of 345 N a distance of 24.0 m. Assume the coefficient of kinetic friction between the crate and the floor is 0.220. a. How much work is done by the worker on the crate? b. How much work is done by the floor on the ...
October 27, 2010

Physics- Work relatedIf 2.0 J of work is done in raising 180 g apple how far is it lifted? I would assume that 2/180 = x but I divided it and it does not sound right.. please someone help.
October 27, 2010

Physics If 2.0 J of work is done in raising a 280g apple, how far is it lifted? I would say F= 2.0/180 but that doesn't really sound right...
October 25, 2010

PhysicsOk so I am not so bad at physics but I find it hard to understand formular like how to use this one mu *m*g= I know its somewhat related to friction but what is teh mu stand for and g too IF someone could plzz translate these symbols to words I would really appreciat it Sorry ...
October 17, 2010

Physics all HELP appreciated! Thank You! A fighter jet is launched from an aircraft carrier with the aid of its own engines and a steam-powered catapult. The thrust of its engines is 2.1 105 N. In being launched from rest it moves through a distance of 87 m and has a kinetic energy of...
October 19, 2009

Habla Espanol?Habla Espanol? si' Thank you for using the Jiskha Homework Help Forum. If you are asking that question correctly, note that the proper punctuation must be at the beginning of the sentence, the tilde is required over the ñ and the language is NOT capitalized. ¿...
June 2, 2007

Obese Heroes....Who are some obese people who have had a positive impact on society and been good role models? Good role models for what, the American Heart Association? This is an odd question. Obesity is a serious condition, becoming very shortly the number 1 preventable Health Concern (...
May 9, 2007